I don't think you can braze to aluminum. To fix it, you would probably have to cut out the dented section and find a way to bond a carbon fiber wrap on it. It can probably be done if you are clever. It's not like CF isn't bonded to aluminum all the time.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter